What is causing split cases ?????AR15

[10xhobby]

I have noticed that some of the reloaded ammo I am loading is causing a split in the case neck, What would cause this ???.



The gun is an AR15 with a 24" SS full heavy barrel, 1:8 twist, Wylde Chamber. I did notice that the cases that split were Mil Spec 5.56, the 223 rem cases seemed to be fine. I am loading AA2230, 19, 20, 22, grains test loads with 75 gr HPBT. Any ideas

[Hoop]

The necks get hard and with repeated firings they will split. Also you will want a different powder, AA2230 is too fast burning and you'll max out at about 23 grains.

[micro911]

You may have to anneal the neck of the cartridge cases. The case neck may have been hardened through reloading.

[XDRoX]

They've just been reloaded too many times. I get about 5 or 6 reloads from 223/556.

[glock7]

They've just been reloaded too many times. I get about 5 or 6 reloads from 223/556.

This^ I usually go 5 times then it goes into the shtf stash.

[264Grendel]

I'll take it

[Bravodigger]

Time to load some .300 blackout

[10xhobby]

I have been happy with the accuracy so far with 21 gr AA2230, Under 1/2" moa at 100 yards. Could the 5.56 case be to thin or not fit the Wylde chamber correctly ??. I shot about 80 rounds and the gun functioned perfectly and was very consistent, I just don't like cases being split, These cases were only reloaded for the second time.

[10xhobby]

head stamp is T W 2 7, these were the only ones that split

[TheExiled]

I have a theory with one my my ARs that its ejector spring is too hard and it's sending the brass into the barrel lugs, as several dozens of casings have been split the same way in the same place from that particular rifle (doesn't look quite like yours, more a straight crack from the rim)

[russ69]

....I shot about 80 rounds and the gun functioned perfectly and was very consistent, I just don't like cases being split, These cases were only reloaded for the second time.

You are eating into your chamber when the hot gas escapes past the cartridge case. You should have stopped shooting that lot. It looks like they are heavily crimped cases and were not annealed enough for reloading.

P.S. Military cases are thick and your neck is probably being overworked.

[6mmintl]

Your loads are too light, should be 23-24 grains with military cases, lots of carbon around neck shoulder.

I suspect too many loads on your military brass, maybe fired in a M249 saw beforehand. What form die set are you using? std. full length, small base, match?

[10xhobby]

I am using Lee full length. I did notice the carbon around the neck also, what causes that ?? Could the 75 grain HPBT heavy bullet be a problem ??

[Beelzy]

Those cases could have started life as machine gun ammo.....MG's really work brass, reducing it's reloading life dramatically.

[SouthCoastTargets]

They've just been reloaded too many times. I get about 5 or 6 reloads from 223/556.

after that, i chop em down to .300 AAC and get another 5 to 6 before taking to scrap yard.